Pro-con introduction: Two-party system rooted in U.S. history

Three's A Crowd

More than two dozen third political parties have tried to crack America's two-party system in presidential elections. The most successful third-party candidate was George Wallace in 1968, who received more than 9 million votes as the American Independent Party candidate. He earned 46 electoral votes. Strom Thurmond, running on the State's Rights ticket, got more than a million votes and 39 electoral votes in 1948. Ralph Nader and the Green Party received more than 2 million votes in 2000.

Some of the political third parties in U.S. history that have appeared on the ballot for president: